a professional bro. This is a person who excels in party related activity with a professional style. They are good at all things party: i.e. drinking, smoking, dancing, talking to the opposite sex, getting out of situations, etc.

We were down to one cup in our beerpong game and Brad just walked up, looked at the cup, and sank it in one shot. A true brofessional.

Noun.
A brofessional is a dude who has devoted himelf fully to bro activities. Obviously this includes beer drinking, watching sports, playing videogames, listening to bro music, hitting on slutty girls.

However, what truly distinguishes the brofessional is that he, upon graduation, finds a job that encourages or accomodates this lifestyle.

"Bro, our lacrosse coach is a brofessional. Did you seem him inhale those beers during flip cup last night at ATO?"
"Yeah, dude. He was crushing everyone at Beer Pong too. I think he hooked up with that freshman whore, Maria. I can't believe he's 27."

The Urban Dictionary T-Shirt

one who is a Professional Bro, who not only excels but pillages in all forms of partying, including, but not limited to: drinking, smoking, smoking cigarettes, talking to girls, handling liquor, and getting out of shit while your drunk.